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### Spin up and spin down

Posted: Sat Oct 19, 2019 11:35 pm
I am having a hard time understanding the concept of different spin states in electrons, I never learned this in High school chem. Can anyone explain how we know if an electron is in a spin up or spin down state?

### Re: Spin up and spin down

Posted: Sat Oct 19, 2019 11:38 pm
He kinda said in class that we didn't need to really know all the details of it but it showed up during electron configuration and I think like if there's two electrons in each orbital state, they can't be parallel, but I am also not completely sure of how we know an electron is spin up or spin down when drawing electron configurations.

### Re: Spin up and spin down

Posted: Sun Oct 20, 2019 12:11 am
For the purposes of this class we don't need to know much beyond what he went over in lecture about what an electron's spin is. However, you could liken the spin of an electron to a the spinning of our earth, as it goes in a single direction, spins on an axis, and it is a property that describes its angular momentum. This is similar to how an electron's spin can either be clockwise `spin up` or counter-clockwise `spin down`.

### Re: Spin up and spin down

Posted: Sun Oct 20, 2019 12:42 am
You only really need to know about the electron spins in the context of the spin magnetic number (the fourth quantum number that you use to describe an electron). We denote the spin with either a +1/2 or a -1/2, which means the electron either spins clockwise or counterclockwise. No 2 electrons in the same atom will have the same 4 quantum numbers, so if one orbital has 2 electrons, one of those electrons will spin clockwise and the other counterclockwise. If there was no magnetic field, both spins would have the same energy, but this doesn't happen in the atomic world.

### Re: Spin up and spin down

Posted: Sun Oct 20, 2019 1:03 am
I'm not sure how to tell if an electron is in up or down spin state, but just know the spin quantum number (ms) can only be -1/2 or +1/2, meaning down spin and up spin respectively.

### Re: Spin up and spin down

Posted: Sun Oct 20, 2019 1:23 am
As the other replies stated, we don't need to understand the exact way the electron spins yet besides that it is either up or down. The reason why there is a need to denote whether the electron spins up or down is to follow Hund's Rule (which states that if there are more than one orbital in a subshell, then you add parallel spins to different orbitals). Which means that when you think about a p-orbital which has 3 orbitals, you would fill the 3 orbitals one electron each first in the same spin direction, and then put in electrons in the other direction (if you have additional electrons) in the orbitals. This gives the lowest energy electron configuration.

### Re: Spin up and spin down

Posted: Sun Oct 20, 2019 3:53 pm
How do we figure out if the electron spins up or spins down?

### Re: Spin up and spin down

Posted: Sun Oct 20, 2019 4:03 pm
To respond to the above person about how to determine spin -- you can determine it by drawing out the diagrams with the up and down arrows. Depending on how many outer electrons an element has, the spin will differ.

### Re: Spin up and spin down

Posted: Sun Oct 20, 2019 4:06 pm
An electron does not actually spin "up" or "down" these are just words we use to describe 2 different states.

### Re: Spin up and spin down

Posted: Sun Oct 20, 2019 7:45 pm
Since this is only 14a I dont think we should know much more about the details of it than he explains in lecture. I think main thing to remember is the -1/2 and +1/2 numbers and that it is always one down and one up in an orbital

### Re: Spin up and spin down

Posted: Sun Oct 20, 2019 7:46 pm
I didn't necessarily understand this in lecture, but do we address it as spinning up or down if the electron travels clockwise or counter-clockwise?

### Re: Spin up and spin down

Posted: Sun Oct 20, 2019 7:51 pm
Just assume the electrons are oriented differently

### Re: Spin up and spin down

Posted: Sun Oct 20, 2019 10:14 pm
Do we always assume that it's spin up and spin down for this class?

### Re: Spin up and spin down

Posted: Sun Oct 20, 2019 10:25 pm
Isn't spin up and spin down just relative? Couldn't it be that one electron spins to the left and one electron spins to the right? The only thing I am confused about is does this mean that the electrons are spinning in exactly 2 different directions? I'm just having trouble conceptualizing this concept. What importance does it have if the electrons spin different directions? What function does it serve and why does it matter